The present invention relates to a water heater, component parts thereof and a system for assembling a water heater.
Conventional water heaters have an upright cylindrical metal tank, an outer jacket spaced from the wall of the tank, and an intervening layer of insulation, such as foam insulation, interposed between the tank and the jacket. Heating elements typically extend horizontally into the tank from a side, and inlet and outlet pipes typically extend through the top of the tank, as well as one or more pipes or openings for additional components such as a temperature and/or pressure relief valve.
In general, conventional water heaters are expensive and labor intensive to build. In addition, the tank is subject to corrosion, necessitating replacement of the entire water heater. At most, limited servicing is possible, and more often servicing is not financially feasible. When problems occur, the entire water heater is scrapped. This is not only time consuming, expensive and inconvenient, but also a waste of resources and a disposal or recycling problem.
The present invention provides a water heater construction allowing easy access and replacement of components for maintenance. In one aspect of the invention, no inner metal tank is used. Rather, a flexible, water impervious liner is fitted in an outer shell. The liner holds the quantity of water to be heated and prevents the water from coming into contact with the shell, which may be metal. The shell is rigid and strong enough to withstand the water pressure without deforming. The shell can have an open top with a peripheral horizontal flange over which a top lip of the liner is fitted. A separate top plate attaches to the flange with standard fasteners for clamping the liner to the shell. Through hull fittings are provided for heating elements at the side and inlet/outlet conduits at the top. If, over time, the liner weakens, ruptures, or becomes damaged, the liner is easily replaceable without having to scrap the other components. Similarly, the construction allows convenient access to virtually all components of the water heater, including the heating elements, so that they can be quickly and easily replaced. A desired amount of insulation can be provided by selecting an appropriate cover or blanket to surround the outer shell. This blanket or cover can be in a form which allows its replacement, such as by use of a drawstring bag having a thin or thick insulating wall.
In another aspect of the invention, the improved construction will reliably indicate if there has been a rupture of the liner. This can be accomplished by providing a top valve communicating with the space between the liner and shell so that water leaking from the liner will be detected. Alternatively or additionally, nontoxic dye can be arranged between the liner and the shell so that should a rupture occur, the dye will bleed into the water and be readily detected.
These and other improvements are described in more detail below.